Alta Mountain, Mountain summit in Kittitas County, US.

Alta Mountain is a 6,275-foot (1,913-metre) summit in Kittitas County, Washington, set in the Alpine Lakes Wilderness of the Cascade Range on land managed by Wenatchee National Forest. Runoff from its slopes drains into tributaries of the Yakima River. The surrounding wilderness holds craggy peaks, deep glacial valleys and granite walls dotted with over 700 mountain lakes.

Alta Mountain lies in the Alpine Lakes Wilderness, where the last glacial retreat began about 14,000 years ago and had moved north of the Canada–US border by 10,000 years ago. The U-shaped cross sections of the river valleys record that recent glaciation, while uplift and faulting, together with glaciation, built the tall peaks and deep valleys of the area.

The mountain stands as part of the Wenatchee National Forest, contributing to the preservation of natural resources in the Pacific Northwest region.

You reach the summit by hiking the Alta Mountain Trail, which is most manageable from July through September when weather conditions are most favorable. Bring sturdy hiking boots and layers to handle changing mountain conditions.

Alta Mountain rises about 204 metres above the surrounding terrain, and its summit lies 7.4 km southwest of Snoqualmie Pass. The nearest higher peak is Chimney Rock, 2,316 metres high and 8.4 km to the north. Runoff from its slopes drains into tributaries of the Yakima River.